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Basis of Presentation and Accounting Policies - Additional Information (Details) € in Millions | 1 Months Ended | 3 Months Ended | 6 Months Ended | 9 Months Ended |
--- | --- | --- | --- | --- | ---
Apr. 30, 2019 USD ($) | Apr. 30, 2019 EUR (€) | Sep. 30, 2020 USD ($) | Jun. 30, 2020 USD ($) | Jun. 30, 2019 USD ($) | Jun. 30, 2020 USD ($) | Sep. 30, 2020 USD ($) | Sep. 30, 2019 USD ($) | Dec. 31, 2019 USD ($)
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Net proceeds from sale of tax credits | $ 103,500,000 | € 92.0 |  |  |  |  |  |  |
Non-cash impairment charge loss |  |  | $ 0 |  |  |  | $ 66,800,000 | $ 64,000,000.0 |
Percentage of consolidated goodwill balance |  |  | 80.00% |  |  |  | 80.00% |  |
Goodwill |  |  | $ 1,198,600,000 |  |  |  | $ 1,198,600,000 |  | $ 1,260,100,000
Minimum |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Percentage of goodwill over fair value of reporting unit |  |  | 20.00% |  |  |  |  |  |
Other Reporting Units | Minimum |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Percentage of goodwill over fair value of reporting unit |  |  | 10.00% |  |  |  |  |  |
Germany |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Non-cash impairment charge loss |  |  |  | $ 66,800,000 | $ 60,200,000 |  |  |  |
United Kingdom |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Percentage of goodwill over fair value of reporting unit |  |  | 12.00% |  |  |  |  |  |
United Kingdom | Discount Rates |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Discount rate for goodwill impairment test (as a percent) |  |  | 11.5 |  |  |  | 11.5 |  |
United Kingdom | Terminal Value Revenue Growth Rate |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Discount rate for goodwill impairment test (as a percent) |  |  | 1.0 |  |  |  | 1.0 |  |
United Kingdom | Terminal Value OUP Margin |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Discount rate for goodwill impairment test (as a percent) |  |  | 3.1 |  |  |  | 3.1 |  |
Netherlands |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Percentage of goodwill over fair value of reporting unit |  |  | 3.30% |  |  |  |  |  |
Goodwill |  |  | $ 114,500,000 |  |  |  | $ 114,500,000 |  |
Netherlands | Maximum |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Percentage of goodwill over fair value of reporting unit |  |  | 10.00% |  |  |  |  |  |
Netherlands | Discount Rates |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Discount rate for goodwill impairment test (as a percent) |  |  | 10.9 |  |  |  | 10.9 |  |
Netherlands | Terminal Value Revenue Growth Rate |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Discount rate for goodwill impairment test (as a percent) |  |  | 2.0 |  |  |  | 2.0 |  |
Netherlands | Terminal Value OUP Margin |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Discount rate for goodwill impairment test (as a percent) |  |  | 3.5 |  |  |  | 3.5 |  |
Northern Europe | Germany |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Goodwill |  |  |  |  |  |  |  |  | 67,200,000
Northern Europe | United Kingdom |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Goodwill |  |  | $ 94,700,000 |  |  |  | $ 94,700,000 |  | 97,300,000
Northern Europe | Netherlands |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Goodwill |  |  | $ 114,500,000 |  |  |  | $ 114,500,000 |  | $ 109,500,000
Northern Europe | Germany |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Non-cash impairment charge loss |  |  |  |  |  | $ 66,800,000 |  |  |

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